A convenient preparative method for esters of amino acids

Abstract

The amino groups of amino acids can be protected by using ethyl ecetoacetate as a ,β-dicarbonyl component. The resulting derivatives are readily alkylated at the carboxyl group by substituted benzyl and other halides. Mild acidolysis then removes the amino protection to give the salt of the amino acid ester. This three-step synthesis can be performed without isolation of intermediates and provides a convenient preparative method for 4-methoxybenzyl, 2,4,6-trimethyl-benzyl, 4-nitrobenzyl, and 4-picolyl esters of amino acids. The products are not racemized.